1. Field of the Invention
This invention relates to a transfer-type electrothermographic recording method and a recording mediun for use with the same.
2. Discussion of Background
The following methods have been conventionally known as electrothermographic recording methods:
(a) A recording method using a recording medium composed of an electroconductive support and a resinous layer formed thereon as disclosed in Japanese Patent Publication 35-14722. A resin of which electrical resistance is decreased when heated, such as polyvinyl chloride, polyethylene, polyester, polystyrene or a styrene - maleic acid copolymer is used for the resinous layer. The resinous layer is electrostatically charged and then heated by applying heat rays thereto in accordance with analogue signals corresponding to an original image, thereby forming an electrostatic image on the resinous layer.
(b) A recording method as disclosed in Japanese Patent Publication 38-14347. An electrothermographic material which is sufficiently transparent to heat rays, such as polyester, chlorinated polyvinyl chloride or vinyl chloride, is superposed on an original image and electrostatically charged. A latent electrostatic image is formed on the electrothermographic material by application of heat rays thereto, and reversely developed with a dry toner to form a visible toner image. The toner image is then fixed.
In the above methods, an infrared ray is applied to the recording medium which is placed in close contact with an original copy. Therefore, a large amount of energy is required for recording, and images with high resolution cannot be obtained. In addition, since these recording media are made of electrically chargeable materials, they are costly.
There has also been proposed a recording method in which a latent electrostatic image is formed on a photoconductor by application of light or on a dielectric material by applying, from a pin electrode, a pulse voltage with a polarity opposite to that of the electric charge on the dielectric material, and is developed with a toner. The toner image is transferred to a sheet of transfer paper and then fixed. This method however has shortcomings in that the process is complicated and an apparatus for use with the method is expensive.